Espresso makers typically force very hot water through tightly packed and very fine espresso powder/coffee grounds. Varying the fineness of the grind, the amount of pressure used to tamp the powder/grounds, or the pressure of the water itself can be used to vary the taste of the espresso. Steam-driven units operate by forcing water through the coffee by using steam or steam pressure. Piston (or lever)-driven machines use a lever, pumped by the operator, to pressurize hot water and send it through the coffee grounds. Lever machines may either by manual piston or by spring piston design. Pump-driven machines operate by a motor-driven or solenoid-driven pump that provides the force necessary for espresso brewing. Some pump-driven machines use a single chamber to both heat the water to the desired brewing temperature and to boil water for frothing milk. Other machines use a single boiler kept at steaming temperature, but water for brewing is passed through a heat exchanger, taking some heat from the steam without rising to the same temperature. Other machines heat water in a separate chamber, which requires two separate boilers, and are referred to as “dual boiler” or “dual heater” machines. In recent years, air-pump driven espresso machines have also been developed, which use compressed air to force the hot water through the coffee grounds (the compressed air comes from either a hand-pump, N20 or CO2 cartridges or an electric compressor). Traditional coffee machines also cause hot water to interact with coffee grounds, and may do so via percolation, drip methods, or french pressing. Improvements to espresso machines and other coffee drink makers continue to be made, and any of the embodiments described herein are intended for use with any of these various types of machines.
Many espresso and coffee drink makers, such as for commercial use, high-end home use, and for use on-board aircraft (or other passenger transport vehicles), are attached directly to the water plumbing of the site or vehicle. This allows the machine to pull as much water as needed from large water tanks so that it is able to brew without being manually refilled. Other designs have built-in water reservoirs that are to be periodically refilled. The embodiments described herein may be used with either of these types of machines.
One feature common to most espresso and coffee drink makers is that they are designed to accept one particular form of powder/coffee grounds. For example, some machines are designed for particular use with certain brands or styles of capsules or pods, or only for use with loose coffee grounds. These machines have internal features that are specifically shaped to hold the particular brand or style of capsule, pod, or loose grounds in order to force water therethough and to create the desired espresso or other coffee drink. For example, a certain brand X machine may be designed for use only with brand X capsules or cups. This can limit the end user or consumer to purchasing only the coffee pods, capsules, or cups that work with the particular purchased machine. For example, if an airline wishes to offer espresso or cappuccino on-board its aircraft, the airline typically selects the coffee form it desires (e.g., a particular brand of pods or capsules or easy serving espresso pods), and then installs the appropriate machines on its fleet.
However, when these machines are purchased in bulk to be installed on a fleet of aircraft, for example, being limited to one form of coffee capsule or pod can be disadvantageous in a number of instances. For example, an aircraft may not wish to be locked into only one supplier for the life of the aircraft fleet that has been fitted with a particular machine brand. A supplier may raise costs to a prohibitive level, may discontinue particular flavors, may change the shape or form of their product packaging, or may not offer options that are green or recyclable, conflicting with a company's desire or mission to be environmentally friendly. There are a number of other reasons why a particular airline may desire interchangeability and flexibility in the types of coffee and espresso it serves. Although the desire for interchangeability has been described with respect to airlines/aircraft usage, it should be understood that there are other instances when interchangeability may also be desired. For example, a particular company or restaurant with multi-office sites may wish to purchase one type of machine for all locations, but to have long-term flexibility on coffee suppliers or interchangeability at individual sites.
Accordingly, it is desirable to provide a universal espresso or other coffee drink maker that provides this interchangeability between variously-packaged coffee grounds.